Our program is concerned with specific aspects of endoplasmic reticulum (ER) and Golgi function and with causes and consequences of alterations in protein glycosylation. ER functions we propose to investigate are regulation of synthesis of enzymes involved in the lipid-linked glycosylation pathway and the mechanism of enzyme retention in the ER. We are also interested in a pleiotropic mutation in yeast that affects most or all ER functions. The Golgi systems that interest us are alpha-mannosidase II, a mammalian liver enzyme we are cloning in lambdal gt11, and GDP- mannose transport into yeast Golgi. We plan to carry out biochemical and molecular studies in both systems. We will continue studies on altered glycosylation by investigating specific mutagenesis of glycosylation sites on chicken ovalbumin and other glycoproteins, and by investigating mechanisms used by transformed cells to alter cell surface glycosylation.